Plug assembly

Abstract

The invention relates to a plug devices for sealing an open end of a pipe which is being tested for structural integrity. The plug assembly has a reduced diameter first portion which is adapted for engagement with the interior of the pipe and a second, enlarged diameter portion which houses a piston that slidably moves within the central opening of the second portion. A compressible flexible packer element mounted on the first portion is compressed by the piston of the second portion to facilitate fluid-tight engagement with the interior of the pipe. The second portion of the assembly is provided with suitable ports for admitting setting and release pressure acting on the piston. One of the plug assemblies has a transverse bore for engagement with an inlet valve for admitting pressurized fluid into the interior of the pipe. A companion plug assembly adapted for engaging the opposite end of the pipe has a transverse bore fitted with a relief valve for allowing escape of air while the pipe is being filled with test fluid and allowing relief of pressure after the test has been completed.

I claim: 
     
       1. A plug assembly for sealing an open end of a pipe, the plug assembly comprising: a first portion adapted for sealing engagement with an interior of the pipe, said first portion comprising a compressible means for facilitating creation of a fluid-tight seal, an elongated tubular mandrel having central opening extending through its entire length, said mandrel carrying a nose portion on its proximal end and a piston means on its distal end, said compressible means being positioned in a surrounding relationship over a part of said mandrel between said nose portion and said piston means;   a second portion fixedly attached to the first portion, said second portion comprising means for applying a compression force on the compressible means of the first portion; and   a means for admitting pressurized fluid into said pipe, said means comprising a transverse port formed in said second housing member in fluid communication with a central opening extending through said piston means, the central opening of the mandrel and with the interior of the pipe through said nose portion.   
     
     
       2. The assembly of claim 1, wherein at least a part of said mandrel extends into said second portion. 
     
     
       3. The assembly of claim 1, wherein said second portion comprises a first housing member mounted in a surrounding relationship about at least a part of said piston means, said piston means being adapted for a limited sliding movement between a first position, applying the compression force on said compressible means, and a second position, releasing the compression force. 
     
     
       4. The assembly of claim 3, wherein said first housing member has an inner wall which is provided with a pair of spaced-apart inwardly extending shoulders, and said piston means is provided with an outwardly extending shoulder which contacts one of said first housing member inner shoulders when the plug assembly is in a sealing engagement with a pipe end. 
     
     
       5. The assembly of claim 3, wherein said second portion further comprises a second housing member co-axially fixedly attached to said first housing member, said second housing member having a reduced diameter portion which fits within said first housing member in a surrounding relationship about a distal end of said piston means. 
     
     
       6. The assembly of claim 5, wherein a proximal end of said second housing member abuts the second inwardly extending shoulder of said first housing member and forms a means for limiting sliding movement of the piston means within the second portion. 
     
     
       7. The assembly of claim 4, wherein said first housing member is provided with a proximal transverse port adjacent one inwardly extending shoulder, so as to allow admission of a piston setting pressure into said first housing member, and a distal transverse port for releasing said piston setting pressure, said distal transverse port being formed adjacent another inwardly extending shoulder of the first housing member. 
     
     
       8. The assembly of claim 6, further comprising means for relieving pressure from interior of the pipe, said pressure relieving means comprising a transverse bore formed in the second housing member adjacent its most distal end. 
     
     
       9. The assembly of claim 1, wherein said nose portion has a reduced diameter tip sized and shaped to facilitate positioning of the nose portion in the pipe open end. 
     
     
       10. A plug assembly for sealing an open end of a pipe, the plug assembly comprising a first portion adapted for sealing engagement with an interior of the pipe, said first portion comprising a compressible means for facilitating creation of a fluid-tight seal and further comprising an elongated tubular mandrel having a central opening extending through its entire length, said mandrel carrying a nose portion on its proximal end, a piston means on its distal end, and said compressible means between said nose portion and said piston means; a second portion fixedly attached to the first portion, said second portion comprising means for applying a compression force on the compressible means of the first portion, and wherein at least a part of said mandrel extends into the second portion; and   a means for admitting pressurized fluid into said pipe, said means comprising a transverse port formed in said second portion in fluid communication with a central opening which extends through said piston means, the central opening of the mandrel and with the interior of the pipe through said nose portion.   
     
     
       11. The assembly of claim 10, wherein said second portion comprises a first housing member mounted in a surrounding relationship about at least a part of said piston means, said piston means being adapted for a limited sliding movement between a first position, applying a compression force on said compressible means, and a second position, releasing the compression force, said second portion further comprising a second housing member coaxially fixedly attached to said first housing member, said second housing member having a reduced diameter part which fits within said first housing member in a surrounding relationship about a distal end of said piston means. 
     
     
       12. The assembly of claim 11, wherein said first housing member has an inner wall which is provided with a pair of spaced-apart inwardly extending shoulders, and said piston means is provided with an outwardly extending shoulder which contacts one of said first housing member shoulders when the plug assembly is in a sealing engagement with a pipe end. 
     
     
       13. The assembly of claim 11, wherein a proximal end of said second housing member abuts the second inwardly extending shoulder of said first housing member and forms a means for limiting sliding movement of the piston means within the second portion. 
     
     
       14. The assembly of claim 12, wherein said first housing member is provided with a proximal transverse port adjacent one inwardly extending shoulder for allowing admission of a piston setting pressure into said first housing member and a distal transverse port for releasing said piston setting pressure, said distal transverse port being formed adjacent another inwardly extending shoulder of the first housing member. 
     
     
       15. The assembly of claim 13, further comprising means for relieving pressure in interior of the pipe, said pressure relieving means comprising a transverse bore formed in the second housing member adjacent its most distal end.